A 4th generation communication system, which is the next generation communication system, is being developed to provide mobility, Quality of Service (QoS), and a high speed service to a broadband wireless access communication system. A representative example thereof is an Institute of Electrical and Electronics Engineers (IEEE) 802.16 communication system.
The IEEE 802.16 communication system uses an Orthogonal Frequency Division Multiple (OFDM)/Orthogonal Frequency Division Multiple Access (OFDMA) scheme for a physical channel. The OFDM or OFDMA scheme has a characteristic of obtaining a best transmission efficiency when transmitting high speed data by maintaining orthogonality between a plurality of subcarriers.
A handover technique of an IEEE 802.16-based broadband wireless communication system includes a hard handover and a Fast Base Station Switching (FBSS). Here, the FBSS is one of mechanisms for reducing a handover delay time, and manages not only a serving base station with which a terminal currently communicates, but also neighbor communicatable base stations as an activation set. Base stations inside the activation set share a Media Access Control (MAC) context related to a terminal, and may perform a pre-handover of making a reservation of a resource for a terminal in advance. Therefore, when a terminal performs switching (or handover) to a base station inside an activation set, latency may be reduced. Generally, a terminal may add/delete a relevant base station to/from an activation set using received signal intensity of a base station.
The broadband wireless communication system may guarantee uplink coverage and use an interference control algorithm in order to obtain a maximum capacity. That is, to guarantee the performance of a cell boundary terminal with an uplink load greater than a proper level, an uplink interference control is essential.
In the conventional uplink scheduling and interference control algorithm, a channel measurement value is reduced by other change factors such as shadowing, so that an error of determining a terminal at a short distance as a cell boundary terminal occurs. Therefore, a low Modulation and Coding Scheme (MCS) level and a small subchannel may be allocated to a terminal at a short distance. In this case, a transmission efficiency of a system is reduced.